Exemplary embodiments of the invention generally relate to aircraft environmental control systems and, more particularly, to an air bearing shaft of an air cycle machine utilized as part of an aircraft environmental control system.
Conventional aircraft environmental control systems (ECS) incorporate an air cycle machine (ACM), also referred to as an air cycle cooling machine, for cooling and dehumidifying air supplied to an aircraft cabin. An ACM may include a centrifugal compressor and a centrifugal turbine mounted for co-rotation on a shaft. Air bearings in the form of journal bearings and thrust bearings are typically used to support rotation of the shaft. The centrifugal compressor further compresses partially compressed air, such as bleed air received from a compressor of a gas turbine engine. The compressed air discharges to a downstream heat exchanger or other system before returning to the centrifugal turbine. The compressed air expands in the turbine to thereby drive the compressor. The air output from the turbine may be utilized as an air supply for a vehicle, such as the cabin of an aircraft.